trying to use AT&T VFD display module

On 12/6/08, Jeff Jonas <jeffj at panix.com> wrote: Nice. I don't have any information on that particular device, but I have fiddled with a number of text-and-button frontpanels over the years. Does that Itron VFD look like it is "formatted" or bare? A formatted VFD would typically have a PCB the same size or smaller permanently affixed to the back of the glass, and that PCB would have a small number of SMT chips on it and possibly a 14x1 or 7x2 0.1" connector pad on it, either direct soldered to the larger board, or perhaps with a connector. A bare VFD would just have its leads coming out of the glass, right to the only PCB you are looking at. If the microcontroller is an MCS51-family part (8051 and on up to quite modern devices), it should be easy to trace out large portions of its circuit with little effort. At 100% schematic usually takes a long time, but there is often much you can do with some of the core circuitry documented. If there are obvious serial interface chips (1488/1489, or MAX232, or perhaps a 9636/9637-type 8-pin DIP), it might be easy to see a) how to talk and listen, and b) if you need voltages other than just +5VDC. VFDs require something odd - perhaps 36V?, and the formatted VFDs I've seen (and unformatted VFDs on HP printer frontpanels) have a switching supply right there so they _do_ only need +5V. Something from a telephone device might be able to reduce +48V down to what it needs locally, since that's a common voltage in switch gear. Tracing buttons to the microcontroller should be easy. If you are lucky, pressing one would cause the MCU to send out events spontaneously. If you are unlucky, you'd need to send the unit some sort of init code or keypad unlock code first. If you take a few photos (especially if they are properly focused), it's possible to divine much from a visual inspection. If you cannot find docs and the VFD looks formatted, it might be worth cutting out the MCU and wiring your own in its place. There are projects around that use PICs and AVRs to talk to LCDs and VFDs that are HD44780-controller-compatible, and many of those also have provisions for buttons and lights. At some point, if you do get it working, especially if you get it working without hardware mods, I can recommend writing an LCDproc driver for it (http://www.lcdproc.org/). That way, you can use existing control software and existing clients to do interesting things with your display without resorting to writing everything from the ground up. I've written several LCDproc drivers for a variety of serial-interfaced devices, and debugged drivers for several other interface types. It's not too hard to do if you know C. I'm interested to see pictures, especially since I already do so much with displays and LCDproc. Good luck, -ethan